Articulated, predominantly concrete mats have numerous uses in retarding earth erosion due to wind, water, or both. Such mats are used in diverse applications as on shorelines, on river beds, at earthen dams, slopes, trenches and elsewhere, such as where revetments are needed.
Typically, such a mat comprises discrete, concrete blocks arranged in a rectangular grid, in which the concrete blocks are joined by cables, ropes, chains, or like elements. As exemplified in Scales U.S. Pat. No. 4,370,075, it is known for such concrete blocks to have holes permitting vegetation to grow therethrough.
As exemplified in Landry, Jr., U.S. Pat. No. 4,227,829, Schaaf U.S. Pat. No. 4,664,552, and Waters U.S. Pat. No. 4,683,156, and in the Scales patent noted above, it is common to join the concrete blocks by cables passing through small holes in the concrete castings, while the concrete blocks are arranged in a rectangular or hexagonal grid. It is cumbersome to pass cables through small holes in the concrete blocks, particularly if many concrete blocks are to be thus joined. Moreover, before and after such a mat has been installed, the concrete blocks tend to shift along the cables.
As exemplified in Crow et al. U.S. Pat. No. 4,375,928, it is known to join the concrete blocks by cables embedded in the concrete blocks, which are cast in forms holding cables being embedded. It is cumbersome to deploy a cable or cables in a concrete-casting form, particularly if the form is used to cast many concrete blocks simultaneously.
In Pilaar U.S. Pat. No. 3,597,928, it is disclosed that such blocks may be adhesively attached, in one layer or in two layers, to a supporting sheet of synthetic mesh. Adhesive attachment may not be entirely satisfactory, particularly if such blocks are exposed to powerful wind or water action.
There has been a need, to which this invention is addressed, for a better way to join discrete, concrete castings, such as pads, slabs, or blocks, in an articulated mat.